Project Summary We have recently identified a class of long ncRNA termed ncRNA-activating (ncRNA-a), which can activate the expression of neighboring protein-coding genes at long distances. Our current data suggest that ncRNA-a function by associating with the co-activator complex, Mediator, to promote DNA looping. The association between ncRNA-a and the Mediator complex will be investigated to understand how specificity for target selection is achieved and to pinpoint the contribution of RNA to transcriptional activation. The three Aims are designed to provide a thorough molecular understanding of the activating ncRNAs and their association with the Mediator complex. Aim1 describes experiments that examine the molecular basis for ncRNA-a nuclear localization and transcriptional activation. Aim 2 describes experiments to delineate the molecular basis of ncRNA-a and the Mediator complex interaction. We will determine whether ncRNA-a is critical for the recruitment of Mediator to its target sites and perform structure/function experiments to assess the importance of ncRNA-a/Mediator interaction in transcriptional activation. Aim3 will assess the molecular basis by which ncRNA-a activates the CDK8 kinase activity. Importantly, recurrent mutations in Med12 subunit of Mediator complex, which is critical for kinase activity, result in development of multiple human cognitive syndromes and a benign smooth muscle neoplasm. Therefore, we will test the hypothesis that such mutations affect the kinase activity of Mediator by disrupting its association with the ncRNA-a.